Using nginx $http_referer to use different static assets - nginx

Question

I'm trying to deploy two different versions of same app on the same nginx-based server. If the URL starts with /v2, then "v2" should be used, otherwise use v1. Example:
http://example.com/v2/x/y/z * runs v2 app
http://example.com/anything/else * runs v1 app
The two different versions of the app are proxied through nginx, and that piece works well.
The issue is that I have two directories of static assets, /static and /cachedassets, that are common to both versions (and both rooted from /home/v1|2/www/public. So, even though a request to http://example.com/v2/x/y/z will initially use the right app, the page that loads will contain references to /static and /cachedassets, without the /v2 prefix, that will incorrectly load from /home/v1/www/public.
I know referer is an imperfect solution. As a temporary stopgap, until I have a chance to craft a more robust solution, I'm trying to use nginx's $http_referer to point to the correct location for these assets. Here's the nginx file:
server {
listen 1.2.3.4
server_name example.com
...
location /v2 {
root /home/v2/www/public;
try_files $uri #proxyv2;
access_log off;
expires max;
}
location ^/(static|cachedassets) {
root /home/v1/www/public;
if ($http_referer ~* "/v2/") {
root /home/v2/www/public;
}
}
location / {
root /home/v1/www/public;
try_files $uri #proxyv1;
access_log off;
expires max;
}
location #proxyv1 {
include uwsgi_params;
uwsgi_pass unix:///tmp/v1-www.sock;
uwsgi_modifier1 5;
}
location #proxyv2 {
include uwsgi_params;
uwsgi_pass unix:///tmp/v2-www.sock;
uwsgi_modifier1 5;
}
...
}
Any thoughts?
Bonus points for a solution where I can easily specify several "v2" prefixes. For example, here I might specify v2, versiontwo, and vtwo, and the following URLs would all invoke the v2 app:
http://www.example.com/v2/something
http://www.example.com/versiontwo/abc
http://www.example.com/vtwo/abc/def/ghi
and of course, http://www.example.com/somethingelse would run v1.
I'm also open to other ideas that don't use http_referer to accomplish this.
Thanks!

Answer 1

Rather than if blocks, use a map variable to set the root. The map can contain a number of arbitrarily complex regular expressions. See this document for more.
For example:
map $http_referer $root {
default "/home/v1/www/public";
~*/v2/ "/home/v2/www/public";
}
server {
...
location ~ ^/(static|cachedassets) {
root $root;
}
...
}